Emily Danforth's teen novel "The Miseducation Of Cameron Post" could have been used as a doorstop when it came out in 2012. It was 480 pages in hardback and controversial enough to banned from some school reading lists. They did not keep it from becoming a young adult bestseller. And now, slimmed down to just its last few chapters, it's a movie that critic Bob Mondello says is a cinematic equivalent of a real page-turner.

BOB MONDELLO, BYLINE: We meet 16-year-old Cameron as she and a girlfriend come home from Bible study, their pastor's words about sin still ringing in their ears.

(SOUNDBITE OF FILM, "THE MISEDUCATION OF CAMERON POST")

STEVEN HAUCK: (As Pastor Crawford) What feels like fun is actually the enemy. And that enemy is closing the noose around your neck.

CHLOE MORETZ: (As Cameron Post) Ruth? Is anyone home?

MONDELLO: Nobody home, they drop their schoolbooks and fall into a clinch, kissing.

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HAUCK: (As Pastor Crawford) While you experiment and play with that yoke like it's a toy and you think, oh, just this once, just a little longer, click - it's got you.

MONDELLO: A week or so later, the click is of a door handle opening as the two girls are caught going a bit further than kissing in the backseat of a car at their high school prom. Consequences are immediate. Cam's aunt bundles her off to God's Promise, an evangelical camp where the promise is that they will pray away the gay.

EHLE: (As Dr. Lydia Marsh) Cameron's already a masculine name. To abbreviate it to something even less feminine only exacerbates your gender confusion.

MORETZ: (As Cameron Post) Right.

MONDELLO: The school's program combines isolating the kids from the outside world with a sort of enforced groupthink to persuade them that their SSA - same-sex attraction - is a temptation from Satan. Picture an iceberg, they're told. Don't fixate on the visible part at the top. That's the sin. Look below the surface for causes. Cam is given a drawing of an iceberg with SSA at the top and told to fill in the rest. Another student offers suggestions.

(SOUNDBITE OF FILM, "THE MISEDUCATION OF CAMERON POST")

UNIDENTIFIED ACTOR #1: (As character) You run, right?

MORETZ: (As Cameron Post) Yeah.

UNIDENTIFIED ACTOR #1: (As character) Just talk about how positive reinforcement for sports messed with your gender identity - they love that - and how your parents gave you too much physical affection or not enough physical affection. Either way, that's why you're gay.

MONDELLO: This story is set, let's note, in 1993, five years before the first episode of "Will & Grace," 12 years before "Brokeback Mountain." There aren't a lot of competing narratives that Cam and the other kids or, for that matter, their guardians can latch onto. Actress Chloe Grace Moretz gives us the title character as a confident, self-aware youngster, then demonstrates that even a confident, self-aware youngster can crack given enough pressure.

(SOUNDBITE OF FILM, "THE MISEDUCATION OF CAMERON POST")

MORETZ: (As Cameron Post) If I told you I was unhappy and that I wanted to come home, would you let me?

UNIDENTIFIED ACTOR #2: (As character) Cam, come on. You have to give it a chance. You know I'm doing this because I love you. Don't you want to have a family someday? I love you, Cammy (ph).

MORETZ: (As Cameron Post) I love you, too.

MONDELLO: The title "The Miseducation Of Cameron Post" tells you where the film's sympathies lie, but it doesn't tell you whether Cam will be worn down. And wearing down the kids is very much the educational method here. Director Desiree Akhavan keeps the outcome up in the air by treating not just her heroine but everyone in the film compassionately. In another movie, Jennifer Ehle's severe camp director would likely come across as little more than a monstrous Nurse Ratched type. But the director has enough faith in her audience to risk making all of the characters complicated, multifaceted and true-to-life. I'm Bob Mondello. Transcript provided by NPR, Copyright NPR.